Re: [Xenomai-help] crash after termination

[Stefan Kisdaroczi <kisda@domain.hid>]

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Am 23.03.2010 09:00, schrieb Jan Kiszka:
> Stefan Kisdaroczi wrote:
>> Am 20.03.2010 16:53, schrieb Jan Kiszka:
>>> Stefan Kisdaroczi wrote:
>>>> hi all,
>>>>
>>>> after termination of my xenomai applications, my box crashed often (3 of 4 times) with xenomai 2.5.1.
>>>> Today I updated to current git-2.5, rebuilt xenomai and the kernel. Still crashes.
>>>> I have captured two traces over a serial connection. I have attached the kernel config, the two
>>>> traces and the cpuinfo (UP x86 Pentium III). Help is welcome. Thank you.
>>> Both crashes seem to be caused by corrupted skbs. There are (at least)
>>> two uncommon network component in your kernel: ARCNET and ISDN. Do you
>>> make use of them or are they just passively loaded? If the former: Can
>>
>> Just passively loaded.
>>
>>> you retry without them? >(The Kernel's ISDN stuff is of, well, mixed
>>> quality, and ARCNET is so old and uncommon that the code /may/ have
>>> bit-rotted -
>>
>> I disable them.
>>
>>> just an attempt to detract the attention from Xenomai. :) )
>>
>> I think the problem is in my apps, but I had some hope that
>> some changes for 2.5.2 (about thread cleanup,fork) would help.
> 
> Is your application partially or fully kernel homed? Because no user
> space application is allowed to crash your host, anything else is a bug
> in the kernel as well.

Hi Jan,

Only user space using the native skin. Some additional notes:
I'm using the freepascal compiler and link against libnative, i dont use gcc.
There is one process starting the other ten processes using fork() & execl().
The tasks do a lot of mode switching between primary/secondary.
The stacksize for the tasks is 1MB. We only use between 4K-16K of stack in our
applications. So there should be still a bit less than 1 MB for socket calls
and printf, is this to low ?

I rebuilt the kernel without arcnet and isdn and disabled smp too, using 2.5.1.
It still crashes every time on termination. If I pull the network connector,
I could start and shutdown the applications 5 times without problem. If the
network is connected, as soon as there is some network activity like ssh/samba
on termination the box crashes. Sometimes it gets even back to the prompt before
crashing. Its a rtl8139 network card, but happens in a virtualbox-vm with a pcnet
card too. In the traces is always a "do_IRQ+0x...", so I think the problem is
related to IRQ-handling.

Stefan

>>
>>> What other network components are actively involved in your scenario?
>>
>> Only TCP/IP (non-realtime). Currently a dozen xenomai native tasks are
>> doing standard socket calls. If everything works, there will be about
>> 60 tasks using socket calls, but its still a long way.
>>
>> I focus now first on another problem I have in my apps with a shared heap,
>> so one question about that: There was no H_NONCACHED flag at the time I
>> did write some library code. I use a rt_heap as shared memory between 8
>> processes on x86. According to the documentation H_NONCACHED is only
>> relevant for ARM, is that true?
> 
> AFAIK, yes.
> 
> Jan
> 



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